diff --git a/web-bundle/resources/test-helpers.js b/web-bundle/resources/test-helpers.js
index c1ff011e0d675a..94d5812cebd4c1 100644
--- a/web-bundle/resources/test-helpers.js
+++ b/web-bundle/resources/test-helpers.js
@@ -159,11 +159,15 @@ function createWebBundleElement(url, resources, options) {
   const script = document.createElement("script");
   script.type = "webbundle";
   const json_rule  = {"source": url, "resources": resources};
-  if (options && options.credentials) {
-    json_rule.credentials = options.credentials;
+  if (options) {
+    if (options.credentials) {
+      json_rule.credentials = options.credentials;
+    }
+    if (options.scopes) {
+      json_rule.scopes = options.scopes;
+    }
   }
   script.textContent = JSON.stringify(json_rule);
-  // TODO(crbug.com/1245166): Support |options.scopes|.
   return script;
 }
 
diff --git a/web-bundle/subresource-loading/script-relative-url-resources.https.tentative.html b/web-bundle/subresource-loading/script-relative-url-resources.https.tentative.html
new file mode 100644
index 00000000000000..9fd35c6f1179ae
--- /dev/null
+++ b/web-bundle/subresource-loading/script-relative-url-resources.https.tentative.html
@@ -0,0 +1,81 @@
+<!DOCTYPE html>
+<title>Subresource loading using relative URLs in the 'resources'</title>
+<link
+  rel="help"
+  href="https://github.com/WICG/webpackage/blob/main/explainers/subresource-loading.md"
+/>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="../resources/test-helpers.js"></script>
+
+<script>
+  window.TEST_WEB_BUNDLE_ELEMENT_TYPE = "script";
+  setup(() => {
+    assert_true(HTMLScriptElement.supports("webbundle"));
+  });
+</script>
+<body>
+  <script>
+    let script;
+
+    function cleanUp() {
+      if (script) {
+        script.remove();
+      }
+    }
+
+    function createScriptWebBundle(resource) {
+      return createWebBundleElement(
+        "../resources/wbn/subresource.wbn",
+        /*resources=*/ [resource]
+      );
+    }
+
+    async function assertResourceCanBeFetched() {
+      const response = await fetch(`../resources/wbn/root.js`);
+      const text = await response.text();
+      assert_equals(text, "export * from './submodule.js';\n");
+    }
+
+    async function assertResourceNotFound() {
+      const response = await fetch(`../resources/wbn/root.js`);
+      const status = await response.status;
+      assert_equals(status, 404);
+    }
+
+    promise_test(async (t) => {
+      t.add_cleanup(cleanUp);
+      script = createScriptWebBundle("root.js");
+      document.body.append(script);
+      await assertResourceCanBeFetched();
+    }, "A relative URL, 'root.js', should be resolved on the bundle's URL");
+
+    promise_test(async (t) => {
+      t.add_cleanup(cleanUp);
+      script = createScriptWebBundle("./root.js");
+      document.body.append(script);
+      await assertResourceCanBeFetched();
+    }, "Use './root.js', starting with dot");
+
+    promise_test(async (t) => {
+      t.add_cleanup(cleanUp);
+      script = createScriptWebBundle("../wbn/root.js");
+      document.body.append(script);
+      await assertResourceCanBeFetched();
+    }, "Use '../wbn/root.js', starting with two dots");
+
+    promise_test(async (t) => {
+      t.add_cleanup(cleanUp);
+      script = createScriptWebBundle("/web-bundle/resources/wbn/root.js");
+      document.body.append(script);
+      await assertResourceCanBeFetched();
+    }, "Use '/web-bundle/resources/wbn/root.js', starting with slash");
+
+    promise_test(async (t) => {
+      t.add_cleanup(cleanUp);
+      script = createScriptWebBundle("unrelated-relative-url.js");
+      document.body.append(script);
+      await assertResourceNotFound();
+    }, "A resource should not be found");
+  </script>
+</body>
diff --git a/web-bundle/subresource-loading/script-relative-url-scopes.https.tentative.html b/web-bundle/subresource-loading/script-relative-url-scopes.https.tentative.html
new file mode 100644
index 00000000000000..b3ecd8fee30d6d
--- /dev/null
+++ b/web-bundle/subresource-loading/script-relative-url-scopes.https.tentative.html
@@ -0,0 +1,84 @@
+<!DOCTYPE html>
+<title>
+  Subresource loading using relative URLs in the 'scopes'
+</title>
+<link
+  rel="help"
+  href="https://github.com/WICG/webpackage/blob/main/explainers/subresource-loading.md"
+/>
+<script src="/resources/testharness.js"></script>
+<script src="/resources/testharnessreport.js"></script>
+<script src="../resources/test-helpers.js"></script>
+
+<script>
+  window.TEST_WEB_BUNDLE_ELEMENT_TYPE = "script";
+  setup(() => {
+    assert_true(HTMLScriptElement.supports("webbundle"));
+  });
+</script>
+<body>
+  <script>
+    let script;
+
+    function cleanUp() {
+      if (script) {
+        script.remove();
+      }
+    }
+
+    function createScriptWebBundle(scope) {
+      return createWebBundleElement(
+        "../resources/wbn/relative-url.wbn",
+        /*resources=*/ [],
+        { scopes: [scope] }
+      );
+    }
+
+    async function assertResourceCanBeFetched() {
+      const response = await fetch("../resources/wbn/relative-url/subdirectory-path.js");
+      const text = await response.text();
+      assert_equals(text, "scriptLoaded('subdirectory-path.js');");
+    }
+
+    async function assertResourceNotFound() {
+      const response = await fetch("../resources/wbn/relative-url/subdirectory-path.js");
+      const status = await response.status;
+      assert_equals(status, 404);
+    }
+
+    promise_test(async (t) => {
+      t.add_cleanup(cleanUp);
+      script = createScriptWebBundle("relative-url");
+      document.body.append(script);
+      await assertResourceCanBeFetched();
+    }, "A relative URL, 'relative-url', should be resolved on the bundle's URL");
+
+    promise_test(async (t) => {
+      t.add_cleanup(cleanUp);
+      script = createScriptWebBundle("./relative-url");
+      document.body.append(script);
+      await assertResourceCanBeFetched();
+    }, "Use './relative-url', starting with dot");
+
+    promise_test(async (t) => {
+      t.add_cleanup(cleanUp);
+      script = createScriptWebBundle("../wbn/relative-url");
+      document.body.append(script);
+      await assertResourceCanBeFetched();
+    }, "Use '../wbn/relative-url', starting with two dots");
+
+    promise_test(async (t) => {
+      t.add_cleanup(cleanUp);
+      script = createScriptWebBundle("/web-bundle/resources/wbn/relative-url");
+      document.body.append(script);
+      await assertResourceCanBeFetched();
+    }, "Use '/web-bundle/resources/wbn/relative-url', starting with slash");
+
+    promise_test(async (t) => {
+      t.add_cleanup(cleanUp);
+      script = createScriptWebBundle("unrelated-scope");
+      document.body.append(script);
+      await assertResourceNotFound();
+    }, "A resource should not be found");
+  </script>
+</body>
diff --git a/web-bundle/subresource-loading/script-relative-url.https.tentative.html b/web-bundle/subresource-loading/script-relative-url.https.tentative.html
deleted file mode 100644
index 8b9a1cae9ef806..00000000000000
--- a/web-bundle/subresource-loading/script-relative-url.https.tentative.html
+++ /dev/null
@@ -1,24 +0,0 @@
-<!DOCTYPE html>
-<title>Subresource loading using relative URLs in the 'resources' attribute</title>
-<link rel="help" href="https://github.com/WICG/webpackage/blob/main/explainers/subresource-loading.md" />
-<script src="/resources/testharness.js"></script>
-<script src="/resources/testharnessreport.js"></script>
-<script src="../resources/test-helpers.js"></script>
-
-<script>
-  window.TEST_WEB_BUNDLE_ELEMENT_TYPE = 'script';
-  setup(() => {
-    assert_true(HTMLScriptElement.supports('webbundle'));
-  });
-</script>
-<body>
-  <script type="webbundle">
-    {
-      "source": "../resources/wbn/static-element.wbn",
-      "resources": ["/web-bundle/resources/wbn/static-element/resources/script.js"]
-    }
-  </script>
-  <script id="script" src="/web-bundle/resources/wbn/static-element/resources/script.js"></script>
-
-  <script src="resources/relative-url-test.js"></script>
-</body>
\ No newline at end of file
diff --git a/web-bundle/subresource-loading/script-reuse-web-bundle-resource.https.tentative.html b/web-bundle/subresource-loading/script-reuse-web-bundle-resource.https.tentative.html
index 7429ae0a033145..55b7e9d85fae34 100644
--- a/web-bundle/subresource-loading/script-reuse-web-bundle-resource.https.tentative.html
+++ b/web-bundle/subresource-loading/script-reuse-web-bundle-resource.https.tentative.html
@@ -16,8 +16,11 @@
     });
 
     const wbn_url = "../resources/wbn/subresource.wbn";
-    const resource1 = "../resources/wbn/root.js";
-    const resource2 = "../resources/wbn/submodule.js";
+    const resource1 = "root.js";
+    const resource2 = "submodule.js";
+
+    const resource1_url = `../resources/wbn/${resource1}`;
+    const resource2_url = `../resources/wbn/${resource2}`;
 
     let script1;
     let script2;
@@ -32,18 +35,18 @@
     }
 
     async function assertResource1CanBeFetched() {
-      const response = await fetch(resource1);
+      const response = await fetch(resource1_url);
       const text = await response.text();
       assert_equals(text, "export * from './submodule.js';\n");
     }
 
     async function assertResource1CanNotBeFetched() {
-      const response = await fetch(resource1);
+      const response = await fetch(resource1_url);
       assert_equals(response.status, 404);
     }
 
     async function assertResource2CanBeFetched() {
-      const response = await fetch(resource2);
+      const response = await fetch(resource2_url);
       const text = await response.text();
       assert_equals(text, "export const result = 'OK';\n");
     }
